Just like the Xperia SP, the update has brought some features and improvements to these three devices. Here's the official changelog:• User interface optimization and smoother graphical experience• New Sony user interface with new home screen look and feel• Sony’s Smart Social Camera and downloadable camera apps• Updated Sony Media apps – “WALKMAN”, Album and Movies apps• New version of Battery STAMINA Mode for prolonging battery lifeSony has also improved the native app portfolio to the latest versions - Messaging, Smart Connect, Small apps, TrackID and Sony Select.And finally STAMINA Mode is now available to these three devices. As for the Android 4.4 update, these devices (include Xperia SP and Xperia ZR too) are still under investigation.Source